CN104852781A - Method and apparatus for high rate data transmission in wireless communication - Google Patents

Abstract

Techniques for utilizing multiple carriers to substantially improve transmission capacity are described. For multi-carrier operation, a terminal receives an assignment of multiple forward link (FL) carriers and at least one reverse link (RL) carrier. The carriers may be arranged in at least one group, with each group including at least one FL carrier and one RL carrier. The terminal may receive packets on the FL carrier(s) in each group and may send acknowledgements for the received packets via the RL carrier in that group. The terminal may send channel quality indication (CQI) reports for the FL carrier(s) in each group via the RL carrier in that group. The terminal may also transmit data on the RL carrier(s). The terminal may send designated RL signaling (e.g., to originate a call) on a primary RL carrier and may receive designated FL signaling (e.g., for call setup) on a primary FL carrier.

Description

Method and apparatus for high rate data transmission in wireless communications

The present application is a divisional application of chinese patent application having an application date of 29/3/2006 and an application number of 200680018751.x entitled "method and apparatus for high rate data transmission in wireless communication".

Claiming priority based on 35U.S.C. § 119

This patent application claims priority from provisional application No.60/666,461 entitled "method and APPARATUS FOR HIGH RATE DATA transfer information associated with COMMUNICATIONS", filed 3/29/2005, assigned to the assignee of the present application and incorporated herein by reference.

Technical Field

The present disclosure relates generally to communication, and more specifically to techniques for high rate data transmission.

Background

Wireless communication systems are widely deployed to provide various communication services such as voice, packet data, broadcast, messaging, and so on. These systems may be multiple-access systems capable of supporting communication for multiple users by sharing the available system resources. Examples of such multiple-access systems include Code Division Multiple Access (CDMA) systems, Time Division Multiple Access (TDMA) systems, Frequency Division Multiple Access (FDMA) systems, and Orthogonal Frequency Division Multiple Access (OFDMA) systems.

Data usage for wireless communication systems continues to increase due to the growing number of users and the emergence of new applications with higher data requirements. However, a given system typically has limited transmission capacity, as determined by the system design. A large increase in transmission capacity is typically achieved by deploying a new generation of systems or a new design of systems. For example, the transition of cellular systems from second generation (2G) to third generation (3G) provides significant improvements in data rates and characteristics. However, new system deployments are capital intensive and often complex.

Accordingly, there is a need in the art for techniques to improve the transmission capacity of a wireless communication system in an efficient and cost-effective manner.

Disclosure of Invention

Techniques for using multiple carriers on the forward and/or reverse links to significantly improve transmission capacity are described herein. The techniques may be used for various wireless communication systems, such as cdma2000 systems. These techniques may provide various advantages because only relatively minor changes are made to existing channel structures designed for single carrier operation.

According to one embodiment of the invention, an apparatus is described that includes at least one processor and a memory. The processor receives an assignment of a plurality of Forward Link (FL) carriers and at least one Reverse Link (RL) carrier. The processor then receives a data transmission on one or more of the plurality of FL carriers.

According to another embodiment of the present invention, a method is provided in which an allocation of a plurality of FL carriers and at least one RL carrier is received. A data transmission is then received on one or more of the plurality of FL carriers.

According to another embodiment of the invention, an apparatus is described, comprising: means for receiving an assignment of a plurality of FL carriers and at least one RL carrier; and means for receiving a data transmission on one or more of the plurality of FL carriers.

According to another embodiment of the invention, an apparatus is described that includes at least one processor and a memory. The processor obtains acknowledgments for packets received on multiple data channels (e.g., F-PDCH), channelizes the acknowledgments for each data channel with an orthogonal code assigned to the data channel to generate a symbol sequence for the data channel, and generates modulation symbols for an acknowledgment channel (e.g., R-ACKCH) based on the symbol sequences for the multiple data channels.

According to another embodiment of the present invention, a method is provided in which acknowledgements for packets received on a plurality of data channels are obtained. The acknowledgements for each data channel are channelized with the orthogonal code assigned to that data channel to generate a sequence of symbols for that data channel. Generating modulation symbols for an acknowledgement channel based on the symbol sequences for the plurality of data channels.

According to another embodiment of the invention, an apparatus is described, comprising: means for obtaining acknowledgements for packets received on a plurality of data channels; means for channelizing the acknowledgements of each data channel using the orthogonal code assigned to that data channel to generate a sequence of symbols for that data channel; and means for generating modulation symbols for an acknowledgement channel based on the symbol sequences for the plurality of data channels.

According to another embodiment of the invention, an apparatus is described that includes at least one processor and a memory. The processor obtains full Channel Quality Indication (CQI) reports for a plurality of FL carriers, each full CQI report indicating a received signal quality for one FL carrier. The processor transmits the full CQI reports for the multiple FL carriers on a CQI channel (e.g., R-CQICH) in different time intervals.

According to another embodiment of the present invention, a method is provided in which full CQI reports for a plurality of FL carriers are obtained, each full CQI report indicating the received signal quality of one FL carrier. Transmitting the full CQI reports for the plurality of FL carriers on a CQI channel for different time intervals.

According to another embodiment of the invention, an apparatus is described, comprising: means for obtaining full CQI reports for a plurality of FL carriers, each full CQI report indicating a received signal quality of one FL carrier; and means for transmitting the full CQI reports for the plurality of FL carriers on a CQI channel for different time intervals.

According to another embodiment of the invention, an apparatus is described that includes at least one processor and a memory. The processor operates in a control-hold mode that allows transmission of a gated pilot, receives a data channel (e.g., P-PDCH) transmitted on a forward link in the control-hold mode, transmits the gated pilot on a reverse link if no other transmissions are being transmitted on the reverse link, and transmits a full pilot on the reverse link if a transmission is being transmitted on the reverse link.

According to another embodiment of the present invention, a method is provided in which a terminal operates in a control-hold mode that allows transmission of a gated pilot. In the control-hold mode, a data channel transmitted on a forward link is received. Transmitting the gated pilot on the reverse link if no other transmissions are being transmitted on the reverse link. Transmitting a full pilot on the reverse link if a transmission is being transmitted on the reverse link.

According to another embodiment of the invention, an apparatus is described, comprising: means for operating in a control-hold mode that allows transmission of a gated pilot; means for receiving a data channel transmitted on a forward link in the control-hold mode; means for transmitting the gated pilot on a reverse link when no other transmissions are being transmitted on the reverse link; and means for transmitting a full pilot on the reverse link when a transmission is being transmitted on the reverse link.

Various aspects and embodiments of the invention are described in more detail below.

Drawings

Fig. 1 shows a wireless communication system.

Fig. 2 illustrates exemplary data transmission on the forward link in cdma 2000.

Fig. 3 illustrates an exemplary multi-carrier structure.

Fig. 4A shows the R-ACKCH structure in cdma2000 revision D.

Fig. 4B and 4C show new R-ACKCH structures that may support up to three and seven R-ACKCHs for multiple FL carriers, respectively.

Fig. 5A shows the R-CQICH structure in cdma2000 revision D.

Fig. 5B shows a new R-CQICH structure that may support multiple FL carriers.

Fig. 6A through 6E illustrate exemplary transmissions on a new R-CQICH.

Fig. 7 illustrates transmission of a full pilot and a gated pilot on the R-PICH.

Fig. 8 shows a process for multi-carrier operation performed by the terminal.

Fig. 9 shows a process for sending an acknowledgement.

Fig. 10 shows a process for sending CQI reports.

Fig. 11 illustrates a process for reducing pilot overhead in multi-carrier operation.

Fig. 12 shows a block diagram of a base station and a terminal.

Detailed Description

The term "exemplary" is used herein to mean "serving as an example, instance, or illustration. Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments.

Fig. 1 shows a wireless communication system 100 with multiple base stations 110 and multiple terminals 120. A base station is generally a fixed station that communicates with the terminals and may also be referred to as an access point, a node B, a Base Transceiver Subsystem (BTS), and/or some other terminology. Each base station 110 provides communication coverage for a particular geographic area 102. The term "cell" can refer to a base station and/or its coverage area based on the context in which the term is used. To improve system capacity, a base station coverage area may be divided into multiple smaller areas, e.g., three smaller areas 104a, 104b, and 104 c. The term "sector" can refer to a fixed station and/or its coverage area that serves a smaller area, based on the context in which the term is used. For a sectorized cell, the base station typically serves all sectors of the cell. The transmission techniques described herein may be used for systems with sectorized cells as well as systems with non-sectorized cells. For simplicity, in the following description, the term "base station" is used generically for a fixed station that serves a sector as well as a fixed station that serves a cell.

Terminals 120 are typically dispersed throughout the system, and each terminal may be fixed or mobile. A terminal may also be called a mobile station, a user equipment, or some other terminology. The terminal may be a cellular telephone, a Personal Digital Assistant (PDA), a wireless device, a handheld device, a wireless modem, or the like. A terminal may communicate with one or more base stations on the forward and/or reverse links at any given moment. The forward link (or downlink) refers to the communication link from the base stations to the terminals, and the reverse link (or uplink) refers to the communication link from the terminals to the base stations.

A system controller 130 is coupled to base stations 110 and provides coordination and control for these base stations. System controller 130 may be a single network entity or a combination of network entities.

The transmission techniques described herein may be used for various wireless communication systems such as CDMA, TDMA, FDMA and OFDMA systems. A CDMA system may implement one or more wireless technologies, e.g., CDMA2000, wideband-CDMA (W-CDMA), and so on. cdma2000 covers IS-2000, IS-856, IS-95 and other standards. TDMA systems may implement wireless technologies such as global system for mobile communications (GSM). The various wireless technologies and standards are known in the art. W-CDMA and GSM are described in documents from an organization named "third Generation partnership project" (3 GPP). Cdma2000 is described in a document from an organization named "third generation partnership project 2" (3GPP 2). Both 3GPP and 3GPP2 documents are publicly available. For clarity, the transmission techniques are described below with specific reference to a CDMA2000 system, which may be a "CDMA 1 x-EVDV", "CDMA 1 x-EVDO", and/or a "1 x" system.

cdma2000 defines a variety of data and control channels that support data transmission on the forward and reverse links. Table 1 lists some of the data and control channels used for the forward and reverse links and provides a short description of each channel. In the description herein, the prefix "F-" denotes a channel for the forward link and the prefix "R-" denotes a channel for the reverse link. The above channels are described in detail in "TIA/EIA IS-2000.2Physical layer Standard for cdma2000Spread Spectrum Systems, Release D" (hereinafter TIA/EIA IS-2000.2) and "TIA/EIA 2000.3Medium Access Control (MAC) Standard for cdma2000Spread Spectrum Systems, Release D" (hereinafter TIA/EIA IS-2000.3) from the telecommunication industry Association, both standards being publicly available. cdma2000 revision D IS also referred to as IS-2000 revision D, or simply "Rev D". The data and control channels are also described in other standard documents for cdma 2000.

TABLE 1

In general, F-PDCH, F-PDCCH, R-ACKCH, and R-CQICH are used for data transmission on the forward link. R-PDCH, R-REQCH, R-PICH, F-ACKCH, and F-GCH are used for data transmission on the reverse link. In general, each channel may convey control information, data, pilot, other transmissions, or any combination thereof.

Fig. 2 illustrates exemplary data transmission on the forward link in cdma 2000. The base station has a plurality of data packets to be transmitted to the terminal. The base station processes each data packet to generate a code packet and further divides the code packet into a plurality of sub-packets. Each subpacket contains enough information to enable the terminal to decode and recover the packet under good channel conditions.

Base station at slave time T₁The first subpacket a1 of packet a is transmitted on the F-PDCH in the first two slots. In cdma2000, one slot has a duration of 1.25 milliseconds (ms). The base station also sends a 2-slot message on the F-PDCCH indicating that transmissions on the F-PDCH are intended for the terminal. The terminal receives and decodes sub-packet A1, determines that packet A was decoded in error, and at time T₂A Negative Acknowledgement (NAK) is transmitted on the R-ACKCH. In this example, the ACK delay is 1 slot. Base station at slave time T₃The first subpacket B1 of packet B is transmitted on the F-PDCH in the first four slots. The base station also sends a 4-slot message on the F-PDCCH indicating that transmissions on the F-PDCH are intended for the terminal. The terminal receives and decodes sub-packet B1, determines that packet B is decoded correctly, and at time T₄On R-ACKCHAn Acknowledgement (ACK) is sent. Base station at slave time T₅The second subpacket a2 of packet a is transmitted on the F-PDCH in one of the time slots starting at (a). The terminal receives sub-packet A2, decodes sub-packets A1 and A2, determines that packet A was decoded in error, and at time T₆The NAK is sent on the R-ACKCH.

The terminal also periodically measures the channel quality of the base station to which data may be transmitted. The terminal identifies the best base station and sends a full Channel Quality Indication (CQI) report and a differential (Diff) Channel Quality Indication (CQI) report on the R-CQICH as described below. The CQI reports are used to select the most suitable base station to send data to the terminal and the suitable data rate for data transmission.

In cdma2000, a base station uses a pseudo-random number (PN) sequence to spectrally spread data at a rate of 1.2288 mega chips per second (Mcps). The base station modulates a carrier signal with the spread data and generates a Radio Frequency (RF) modulated signal having a bandwidth of 1.2288 MHZ. The base station then transmits the RF modulated signal on the forward link at a particular center frequency. Since data is modulated for a single carrier, it is referred to as single carrier CDMA. The capacity of the forward link is determined by the number of data bits that can be reliably transmitted in a 1.2288MHz RF modulated signal. On the reverse link, the terminal also spectrally spreads the data with the PN sequence at 1.2288Mcps and transmits the spread data at a particular carrier frequency. The capacity of the reverse link is determined by the number of data bits that can be reliably transmitted on the data channel assigned to the terminal.

In one scheme, multiple carriers are used on a link to achieve significant capacity improvement on the link. In one embodiment, a chip rate of 1.2288Mcps is used for each of the multiple carriers, which is the same chip rate used for single carrier CDMA. This allows hardware designed for single carrier CDMA to also support multi-carrier CDMA.

Fig. 3 shows a diagram of one embodiment of a multi-carrier structure 300. In this embodiment, K carriers are available on the forward link and M carriers are available on the reverse link, where K >1 and M ≧ 1. A Forward Link (FL) carrier is a carrier on the forward link and a Reverse Link (RL) carrier is a carrier on the reverse link. The carrier may also be referred to as an RF channel, a CDMA channel, etc. The K FL carriers and the M RL carriers are arranged into G groups, wherein G is more than or equal to 1. In general, any number of carrier groups may be formed, and each group may include any number of FL carriers and any number of RL carriers.

In the embodiment shown in fig. 3, each carrier group includes at least one FL carrier and one RL carrier, such that G ≧ M and K ≧ M. As shown in fig. 3, carrier group 1 includes FL carriers 1 to N₁And RL Carrier 1, Carrier group 2 includes FL Carrier N₁+1 to N₁+N₂And RL Carrier 2, and so on, Carrier group M includes FL Carrier K-N_M+1 to K and RL carrier M. In general, N₁To N_MMay be the same or different. In one embodiment, N_m≤4，_mUp to four FL carriers are associated with a single RL carrier in each carrier group, M ….

The multi-carrier structure 300 supports multiple system configurations. Configurations with multiple FL carriers and multiple RL carriers may be used for high rate data transmission on the forward and reverse links. A configuration with multiple FL carriers and a single RL carrier may be used for high rate data transmission on the forward link. A configuration with a single FL carrier and multiple RL carriers may be used for high rate data transmission on the reverse link. The appropriate configuration may be selected for the terminal based on a variety of factors, such as available system resources, data requirements, channel conditions, and so forth.

In one embodiment, the FL and RL carriers have different importance. For each group, one (e.g., the first) FL carrier in the group is designated as a group FL primary carrier (groupFL primary), and each of the remaining FL carriers in the group (if any) is designated as a group FL auxiliary carrier (group FL auxiliary). One (e.g., a first) FL carrier of the K FL carriers is designated as a primary FL carrier. Similarly, one (e.g., the first) RL carrier of the M RL carriers is designated as the primary RL carrier.

A terminal may be assigned any number of FL carriers, with one FL carrier being designated as the primary FL carrier for the terminal. A terminal may also be assigned any number of RL carriers, with one RL carrier being designated as the primary RL carrier for the terminal. Different terminals may be assigned different sets of FL and RL carriers. Further, based on those factors described above, different sets of FL and RL carriers may be assigned to a given terminal over time.

In one embodiment, the terminal uses the primary FL and RL carriers to implement the following functions:

initiate a call on the primary RL carrier,

on the primary FL carrier, receiving signaling during call setup,

performing layer three signaling handover procedure on the primary FL carrier, an

Selecting the serving base station for FL transmission based on the primary FL carrier.

In one embodiment, the group FL primary carrier in each carrier group controls the RL carriers in that group. The set FL primary carrier may be used for the following functions:

power control of transmission for R-PICH,

rate control for R-PDCH transmission,

sends an acknowledgement (on the F-ACKCH) for the reverse link transmission,

sending a MAC control message to the terminal (on the F-PDCCH), an

Send forward grant message to terminal (over F-GCH).

The data and control channels in cdma2000 revision D are designed for data transmission on a single carrier. Certain control channels may be modified to support data transmission on multiple carriers. The modification may be such that: (1) the modified control channel is backward compatible with the control channel in cdma2000 revision D; and (2) new changes can be easily implemented, for example, in software and/or firmware, which can reduce the impact on hardware design.

A base station may transmit data to a terminal on the forward link on any number of FL carriers in any number of carrier groups. In one embodiment, the RL carriers in each group transmit R-ACKCH and R-CQICH that support all FL carriers in the group. In this embodiment, the R-ACKCH conveys an acknowledgement for a packet received on the F-PDCH for all FL carriers in the group. The R-CQICH provides CQI feedback for all FL carriers in the group.

1.R-ACKCH

In another aspect, a new R-ACKCH structure that can support data transmission on multiple FL carriers is described. A terminal may monitor multiple FL carriers in a given group while transmitting on a single RL carrier as shown in fig. 3. The terminal may receive multiple packets on multiple F-PDCHs transmitted on the multiple FL carriers. The terminal may acknowledge the multiple packets via a single R-ACKCH transmitted on a single RL carrier. The R-ACKCH may be designed to have a function of transmitting acknowledgements for one or more packets according to the number of received FL carriers.

Fig. 4A shows a block diagram of an R-ACKCH structure 410 used in cdma2000 revision D. One R-ACKCH bit is generated in each 1.25ms frame, which is one slot. The R-ACKCH bit may have the following cases: (1) if the packet is decoded correctly, the R-ACKCH bit is ACK; (2) the R-ACKCH bit is a NAK if the packet is decoded in error; or (3) the R-ACKCH bit is a null bit if there are no packets to acknowledge. The R-ACKCH bits are repeated 24 times by the symbol repetition unit 412 to generate 24 identical modulation symbols, which are further processed and transmitted on the R-ACKCH.

FIG. 4B shows a block diagram of an embodiment of a new R-ACKCH structure 420 that can support up to four R-ACKCHs for up to four FL carriers. The four R-ACKCHs may also be considered as four subchannels of a single R-ACKCH and may be referred to as reverse acknowledgement subchannels (R-ACKSCH). In the following description, the acknowledgement channel for each FL carrier is referred to as R-ACKCH instead of R-ACKSCH.

Fig. 4B shows the case where three R-ACKCHs are used for three FL carriers, also referred to as CDMA channels 0, 1, and 2. The R-ACKCH for each CDMA channel is implemented using a corresponding set of signal point mapping units 422, walsh covering units 424, and repetition units 426. CDMA channels 0, 1 and 2 are assigned 4-chip Walsh codes, respectivelyAnd. The walsh code IS also called a walsh function or walsh sequence and IS defined in TIA/EIA IS-2000.2.

One R-ACKCH bit is generated in each 1.25ms frame (or slot) for each CDMA channel. For CDMA channel 0, signal point mapping unit 422a maps the R-ACKCH bits for CDMA channel 0 to +1, -1, or 0, respectively, based on whether the R-ACKCH bits are ACK, NAK, or null bits. Walsh covering unit 424a uses the 4-chip Walsh code assigned to CDMA channel 0The mapped values are covered. The implementation of walsh covering is by the following steps: (1) the mapped values are repeated four times; and (2) multiplying the four identical values by the Walsh codeTo generate a sequence comprising four symbols. The repeating unit 426a repeats the 4-symbol sequence six times, thereby generating a sequence of 24 symbols for CDMA channel 0. The processing for CDMA channels 1 and 2 is similar to the processing for CDMA channel 0.

In each slot, a summer 428 sums the three 24-symbol sequences from the repetition units 426a, 426b, and 426c for CDMA channels 0, 1, and 2, respectively, and provides 24 modulation symbols corresponding to the slot. These modulation symbols are further processed and transmitted. The base station can recover the R-ACKCH bits for each CDMA channel by performing inverse decovering using the walsh code allocated to the CDMA channel.

FIG. 4C shows a block diagram of an embodiment of a new R-ACKCH structure 430, which may support, for example, up to eight R-ACKCHs for up to eight FL carriers. Fig. 4C shows the case where seven R-ACKCHs are used for seven FL carriers, which are also referred to as CDMA channels 0 through 6. The R-ACKCH for each CDMA channel is implemented using a set of signal point mapping units 432, walsh covering units 434, and repetition units 436. CDMA channels 0 through 6 are assigned 8-chip Walsh codes, respectivelyToWalsh codes are defined in TIA/EIA IS-2000.2.

For each CDMA channel, the signal point mapping unit 432 maps the R-ACKCH bits for the CDMA channel to +1, -1, or 0. A walsh covering unit 434 covers the mapped values with the 8-chip walsh code assigned to the CDMA channel and provides a sequence of eight symbols. Repetition unit 436 repeats the 8-symbol sequence three times, generating a sequence of 24 symbols for the CDMA channel. In each slot, a summer 438 sums the seven 24-symbol sequences from the repetition units 436a through 436g, respectively, for CDMA channels 0 through 6 and provides 24 modulation symbols corresponding to the slot. These modulation symbols are further processed and transmitted.

FIGS. 4B and 4C illustrate exemplary R-ACKCH structures 420 and 430, which support multiple R-ACKCHs and are backward compatible with the current R-ACKCH structure 410 shown in FIG. 4A. Walsh codes are utilized if a CDMA channel is being receivedOrThe R-ACKCH bits for the CDMA channel are processed and the R-ACKCH bits for all other CDMA channels are set to null bits. Thus, the output of the adder 428 or 438 will be the same as the output of the repeat unit 412 in FIG. 4A. The additional CDMA channel can be supported by transmitting R-ACKCH bits for the additional CDMA channel using other walsh codes. The repetition factor is reduced from 24 to 6 or 3 depending on the length of the walsh code.

The R-ACKCH structures shown in fig. 4B and 4C can recover R-ACKCH bits using hardware designed for the R-ACKCH structure shown in fig. 4A. The hardware may generate 24 received symbols for the R-ACKCH in each slot. Decovering the 24 received symbols with walsh codes can be performed in software and/or firmware, which can reduce the impact of upgrading a base station to support multi-carrier operation.

Other structures may also be used to implement multiple R-ACKCHs and would be within the scope of the present invention. For example, multiple R-ACKCHs can be time division multiplexed and transmitted in different intervals of a given slot.

2.R-CQICH

In another aspect, a new R-CQICH structure that can support CQI feedback for multiple FL carriers is described. A terminal may monitor multiple FL carriers in a given group while transmitting on a single RL carrier as shown in fig. 3. The multiple FL carriers may observe different channel conditions (e.g., different fading characteristics) and may obtain different received signal qualities at the terminal. It is desirable for the terminal to be able to provide CQI feedback for as many FL carriers as possible allocated so that the system can select the appropriate FL carriers to use for transmitting data and the appropriate rate for each selected FL carrier. If the system configuration includes a single RL carrier, the terminal may send CQI feedback for all FL carriers via the single RL carrier on the single R-CQICH. The R-CQICH may be designed with the capability to transmit CQI feedback for one or more FL carriers.

In cdma2000 revision D, the R-CQICH may operate in one of two modes, a full mode or a differential mode, in each 1.25ms frame (or slot). In the full mode, a full CQI report including a 4-bit value is transmitted on the R-CQICH. The 4-bit CQI value conveys the received signal quality of one CDMA channel. In the differential mode, a differential CQI report including a 1-bit value is transmitted on the R-CQICH. The 1-bit CQI value conveys the difference in received signal quality between the current and previous time slots for a CDMA channel. The full and differential CQI reports may be generated as described in TIA/EIA IS-2000.2.

Fig. 5A shows a block diagram of an R-CQICH structure 510 used in cdma2000 revision D. For a CDMA channel, either a 4-bit or 1-bit CQI value may be generated in each 1.25ms frame (or slot) depending on whether a full mode or a differential mode is selected. The 4-bit CQI value is also referred to as a CQI value sign. The 1-bit CQI value is also referred to as a differential CQI symbol. The block encoder 512 encodes the 4-bit CQI value using a (12, 4) block code (block code) to generate a codeword having 12 symbols. The symbol repetition unit 514 repeats the 1-bit CQI value 12 times to generate 12 symbols. The switch 516 selects the output of the block encoder 512 for the full mode or the repeat unit 514 for the difference mode.

A CQI report may be sent to a particular base station by covering the report with the walsh code assigned to that base station. A walsh covering unit 518 receives the 3-bit walsh code for the base station selected to serve the terminal and generates a corresponding 8-chip walsh sequence. Unit 518 also repeats the 8-chip walsh sequence 12 times and provides 96 walsh chips in each slot. A modulo-2 adder 520 adds the symbols from switch 516 to the output of walsh cover 518, providing 96 modulation symbols in each slot. The walsh covering unit 518 and adder 520 pair the 3-bit walsh codes for the selected base stationEach symbol of off 516 is covered efficiently. The channel point mapping unit 522 maps each modulation symbol to a +1 or-1 value. Walsh covering section 524 uses Walsh codesCovers each mapped value from unit 522 and provides output symbols, which are further processed and transmitted on the R-CQICH.

The new R-CQICH structure may support either full mode or differential mode for one or more FL carriers. In one embodiment, full CQI reports for different FL carriers in a group are sent in different time slots in a TDM fashion. In one embodiment, for a given time slot, the differential CQI reports for all FL carriers in a group are jointly encoded and transmitted together in that time slot. Joint coding of differential CQI reports is more efficient than individual coding of a single differential CQI report. The repetition in block 514 may be replaced with more efficient coding.

Fig. 5B shows a block diagram of an embodiment of a new R-CQICH structure 530 that may provide CQI feedback for multiple CDMA channels. In this embodiment, a block encoder 532 encodes a 4-bit CQI value for one CDMA channel with a (12, 4) block code to generate a codeword having 12 symbols. The block encoder 534 jointly encodes the N1-bit CQI values for the N CDMA channels with a (12, N) block code to generate a codeword having 12 symbols. The block coding rate (R) is equal to the number of input bits/number of output bits, or R-4/12 for a (12, 4) block code and N/12 for a (12, N) block code. Different coding rates generate different amounts of redundancy and require different received signal quality for reliable reception. Thus, different amounts of transmit power are used for the codewords from block encoder 534 depending on the number of CDMA channels N.

The switch 536 selects the output of the block encoder 532 for the full mode or the block encoder 534 for the differential mode. Walsh covering element 538, adder 540, signal point mapping element 542, and walsh covering element 544 process the symbols from switch 536 in the same manner as described for elements 518, 520, 522, and 524, respectively, in fig. 5A. Walsh covering element 544 provides output symbols that are further processed and transmitted on the R-CQICH.

The block encoding by encoder 534 may be represented by the following matrix:

y＝u·Gequation (1)

Wherein,u＝[u₀u₁… u_k-1]is a 1x k row vector corresponding to a sequence of 1-bit CQI values,

u₀is a vectoruIs selected to be the first input bit of (a),

y＝[y₀ y₁ … y_n-1]is a1 xn row vector, y, corresponding to the encoder output codeword₀Is a vectoryA first output bit of (a), and

Gis a k × n generator matrix for block coding.

The block code is typically specified in its generator matrix. Different block codes may be defined for different values of N from 2 to 7 to support up to 7 CDMA channels. The block code corresponding to each N value may be selected to obtain good performance, which may be measured by the minimum distance between codewords. Table 2 lists exemplary block codes corresponding to N-2 to 7. The block codes in table 2 have the largest possible minimum distance between codewords of linear block codes.

TABLE 2

The block coding corresponding to N ═ 1 may correspond to the 12 × bit repetition performed by unit 514 in fig. 5A. In the embodiment shown in table 2, the (12, 2) block code comprises a (3, 2) block code followed by 4 x sequence repetition thereof. The generator matrix for the (12, 4) block code in encoder 534 is the same as the generator matrix for the (12, 4) block code in encoders 512 and 532. The (12, 2), (12, 3), (12, 4), (12, 5), (12, 6) and (12, 7) block codes in table 2 have minimum distances of 8, 6,4 and 4, respectively. Other generator matrices may also be defined and used for the block code used for differential CQI reporting.

Fig. 5B illustrates an exemplary R-CQICH structure 530 that supports CQI feedback for multiple CDMA channels and is backward compatible with the current R-CQICH structure 510 shown in fig. 5A. If only one CDMA channel is received, the full CQI report for that CDMA channel can be processed using a (12, 4) block code, the differential CQI report can be processed using a 12 x bit repetition, and the output of walsh covering element 544 will be the same as the output of walsh covering element 524 in fig. 5A. Additional CDMA channels may be supported by (1) sending full CQI reports for the CDMA channel in different time slots and (2) jointly sending differential CQI reports for the CDMA channel in the same time slot.

The R-CQICH structure shown in fig. 5B enables recovery of full and differential CQI reports for multiple CDMA channels by making minor changes to the R-CQICH structure shown in fig. 5A. Hardware for the physical layer may block decode the full CQI report. Demultiplexing of the complete CQI reports for different CDMA channels may be performed at the Medium Access Control (MAC) layer. Block decoding of differential CQI reports may be performed at the physical or MAC layer.

Other architectures may be used to implement the R-CQICH for multiple CDMA channels as well, which would be within the scope of the present invention. For example, full CQI reports for multiple CDMA channels may be block coded and sent in the same time slot. As another example, differential CQI reports for a subset of multiple CDMA channels may be sent in one time slot.

A terminal may be assigned multiple FL and RL carrier groups as shown in fig. 3. For each carrier group, the R-CQICH transmitted on the RL carriers in the group may convey CQI reports for the FL carriers in the group, as described in fig. 5B. The CQI reports may be sent in a number of ways.

Fig. 6A through 6E illustrate some exemplary transmissions on the R-CQICH. In these figures, full CQI reports are represented by higher boxes and differential CQI reports are represented by shorter boxes. The high level of the box roughly indicates the amount of transmit power used to send the CQI report. The value in each box indicates the FL carrier reported by the CQI report sent in that box.

Fig. 6A shows the transmission of full CQI and differential CQI reports for two FL carriers 1 and 2 over an R-CQICH. In this example, a full CQI report for FL carrier 1 is sent in one time slot, then differential CQI reports for FL carriers 1 and 2 are sent in some number of time slots, then a full CQI report for FL carrier 2 is sent in one time slot, then differential CQI reports for FL carriers 1 and 2 are sent in some number of time slots, then a full CQI report for carrier 1 is sent in one time slot, and so on. In general, the full CQI report for each FL carrier may be sent at any rate, and the same or different reporting rates may be used for multiple FL carriers. In one embodiment, a full CQI report is sent in one (e.g., first) slot of each 20ms frame, and a differential CQI report is sent in the remaining 15 slots of the frame. The full CQI reports for FL carriers 1 and 2 may alternate as shown in fig. 6A, or may be multiplexed in other ways.

Fig. 6B shows the transmission of a full CQI report for two FL carriers 1 and 2 on the R-CQICH. In this example, a full CQI report for FL carrier 1 is sent in one time slot, then a full CQI report for FL carrier 2 is sent in the next time slot, then a full CQI report for FL carrier 1 is sent in the next time slot, and so on.

Fig. 6C shows the transmission of full CQI and differential CQI reports for three FL carriers 1, 2 and 3 on R-CQICH, with a repetition factor of 2 or REP-2. In this example, a full CQI report for FL carrier 1 is sent in the first two time slots of the 20ms frame, then differential CQI reports for FL carriers 1, 2, and 3 are sent in each of the remaining time slots of the frame, then a full CQI report for FL carrier 2 is sent in the first two time slots of the next 20ms frame, then differential CQI reports for FL carriers 1, 2, and 3 are sent in each of the remaining time slots of the frame, then a full CQI report for FL carrier 3 is sent in the first two time slots of the next 20ms frame, then differential CQI reports for FL carriers 1, 2, and 3 are sent in each of the remaining time slots of the frame, then a full CQI report for FL carrier 1 is sent in the first two time slots of the next 20ms frame, and so on. The differential CQI report may be sent in two consecutive time slots, similar to the full CQI report, or may be sent in a single time slot.

Fig. 6D shows the transmission of a full CQI report for three FL carriers 1, 2 and 3 on R-CQICH, where the repetition factor is 2. In this example, a full CQI report for FL carrier 1 is sent in two time slots, then a full CQI report for FL carrier 2 is sent in the next two time slots, then a full CQI report for FL carrier 3 is sent in the next two time slots, then a full CQI report for FL carrier 1 is sent in the next two time slots, and so on.

Fig. 6E shows the transmission of a full CQI report for three FL carriers 1, 2 and 3 on R-CQICH with a repetition factor of 2 and with two switching slots. In this example, full CQI reports for FL carriers 1, 2, and 3 are sent in the same manner as described above for fig. 6D. However, the last four slots of the 20ms frame are used to send a switch slot pattern (denoted as "s" in fig. 6E), which is a message to switch to the new serving base station.

As shown in fig. 6A-6E, time division multiplexing of full CQI reports for all FL carriers results in a reporting rate of full CQI reports for a given FL carrier decreasing with increasing number of FL carriers in the group. For example, if a group includes 7 FL carriers, a full CQI report may be sent at a rate of 140ms every 7 × 20ms for each FL carrier. The joint coding of the differential CQI reports for all FL carriers results in the reporting rate of the differential CQI reports being independent of, and unaffected by, the number of FL carriers in the group. The slot map "puncture" (or alternative) full CQI reporting is switched when switching to a new cell. The puncturing may not affect all FL carriers equally. In the example shown in fig. 6E, the switching slot map affects FL carriers 1 and 2, but not FL carrier 3.

In one embodiment, a terminal selects a single base station for data transmission on the forward link. The base station may be selected based on the received signal quality measured at the terminal for the primary FL carrier, all of the allocated FL carriers, or a subset of the allocated FL carriers. The R-CQICH for all RL carriers uses walsh cover for the selected base station and thus points to the same cell. The selection of a single base station avoids out-of-order transmissions on the forward link and potential negative impacts on the Radio Link Protocol (RLP). In the forward direction, RLP frames are typically pre-compressed (pre-pack) at a Base Station Controller (BSC) and then forwarded to the base station for transmission to the terminal. Thus, out-of-order transmission of RLP frames can be avoided by transmitting from a single base station.

In another embodiment, a terminal may select multiple base stations for data transmission on the forward link. As described above, since the fading characteristics may be different for different FL carriers, this embodiment enables the terminal to select an appropriate base station for each FL carrier or each group of FL carriers, which may improve overall throughput.

3.R-PICH

It is desirable to reduce the reverse link overhead for data transmission on the forward link. This may be achieved by allocating a single carrier group comprising multiple FL carriers and a single RL carrier to the terminal. Data may be sent on multiple FL carriers and acknowledgments and CQI feedback may be efficiently sent on a single RL carrier.

In certain cases, multiple RL carriers may be used. For example, the base station may not support the new R-ACKCH and R-CQICH structures described above. In this case, each FL carrier can be associated with one RL carrier that supports R-ACKCH and R-CQICH for the FL carrier.

In cdma2000 revision D, the terminal sends a pilot on the R-PICH to help the base station detect the reverse link transmission. If a single RL carrier is allocated, the pilot overhead is shared among all FL carriers associated with that RL carrier. However, if multiple RL carriers are allocated and if the R-PICH is transmitted on each RL carrier to support the R-ACKCH and R-CQICH, then the pilot overhead can be significant for low data rates on the reverse link. Reduction of pilot overhead can be achieved by using a control-hold mode.

Fig. 7 illustrates transmission of full and gated pilots on the R-PICH. Full pilots are pilot transmissions in each slot with a pilot gating rate of 1. The control-hold mode defined in cdma2000 revision D (or simply "revision D control-hold mode") supports pilot gating rates of 1/2 and 1/4. As shown in fig. 7, gated pilots are pilot transmissions in certain slots, or more specifically, every other slot for a pilot gating rate of 1/2 and every fourth slot for a pilot gating rate of 1/4.

In cdma2000 revision D, the base station typically places the terminal in the control-hold mode by sending a layer three message after the control-hold timer expires. For example, if the base station does not receive any data from the terminal and does not transmit any data to the terminal within a certain period of time, the base station may transmit a layer three message to the terminal to place it in the control-hold mode. The transition out of the control-hold mode is triggered if new data arrives at the base station or terminal. If new data arrives at the terminal, the terminal autonomously transitions out of the control-hold mode and begins transmitting full pilot and data on the reverse link. The base station detects that the terminal has transitioned out of the control-hold mode and decodes the data sent with the full pilot. If new data arrives at the base station, the base station first wakes up the terminal by sending a MAC message on the F-PDCCH. In the control-hold mode, the terminal does not process the F-PDCH in order to save power.

Many applications have the characteristic of asymmetric data traffic and may require multiple F-PDCHs on multiple FL carriers. Therefore, multiple reverse pilots may need to be transmitted on multiple RL carriers to support multiple F-PDCHs. In addition to the reverse pilot, traffic on the secondary RL carrier may include only CQI reports on the R-CQICH and acknowledgements on the R-ACKCH. In this case, the use of the control-hold mode can significantly reduce the reverse link overhead on the secondary RL carrier.

However, the revision D control-hold mode is not directly applied to the auxiliary RL carrier for the following reasons. First, in revision D control-hold mode, the terminal does not decode the F-PDCH. Second, the terminal needs to transition out of the revision D control-hold mode before transmitting on the R-ACKCH, and a third layer message from the base station is needed to set the terminal back to the control-hold mode. It is not desirable that the layer three message must be transmitted each time the terminal transmits on the R-ACKCH. In addition, since the base station transmits the layer three message after the control-hold timer expires (typically on the order of several hundred milliseconds), the full pilot is transmitted on the reverse link during this time.

In another aspect, a "secondary" control-hold mode is defined for use on a secondary RL carrier. In one embodiment, the secondary control-hold mode differs from the revision D control-hold mode in that:

the terminal may process the F-PDCH during the secondary control-hold mode,

the terminal can send the acknowledgement on the R-ACKCH without transitioning out of the secondary control-hold mode,

if the F-PDCH is successfully decoded, the terminal can autonomously send full pilots and acknowledgements on the R-ACKCH, an

The terminal may continue with pilot gating after completing R-ACKCH transmission. Different and/or other characteristics may also be used to define the secondary control-hold mode.

To reduce pilot overhead on the reverse link, a revision D control-hold mode may be used on the primary RL carrier, while a secondary control-hold mode may be used on each secondary RL carrier. Both versions of the control-hold mode may support efficient operation of multiple RL carriers in multi-carrier operation.

In one embodiment, the control-hold mode may be defined independently for each RL carrier. The following may occur:

the primary RL carrier is in active mode and any number of secondary RL carriers may be in control-hold mode. The terminal may process the F-PDCH of the secondary RL carrier and may transmit on the R-ACKCH without leaving the control-hold mode.

All RL carriers are in control-hold mode. The terminal does not process the F-PDCH and does not transmit on the R-ACKCH without leaving the control-hold mode. This is a power saving mode.

4.R-REQCH

The terminal may transmit various types of information to the base station over the R-REQCH. The trigger for transmitting the R-REQCH message in cdma2000 revision D may also be used as a trigger for transmitting the R-REQCH message in multicarrier operation. In one embodiment, the terminal sends an R-REQCH message on the primary RL carrier to communicate service related information to the base station. For data transmission on all RL carriers, one buffer may be maintained for each service. The service related information may include a buffer size and watermark crossing (watermark crossing). In one embodiment, the terminal sends R-REQCH messages on the primary and secondary RL carriers to convey the power headroom (headroom) for these RL carriers. The power reporting trigger for each RL carrier may be used to send R-REQCH messages to convey the power headroom for that RL carrier.

5.Scheduling

The terminals may be scheduled for data transmission on the forward and reverse links in a number of ways. Multiple carriers may be scheduled in a centralized manner or each carrier may be scheduled in a distributed manner. In one embodiment, a terminal is scheduled with a centralized scheduler for data transmission on multiple carriers. The centralized scheduler may support a flexible scheduling algorithm that may use the CQI information on all carriers to improve throughput and/or provide a desired quality of service (QoS). In another embodiment, a distributed scheduler is used for each carrier and the terminals are scheduled on that carrier. The distributed schedulers for the different carriers may operate independently of each other and may reuse the existing scheduling algorithm of cdma2000 revision D.

A terminal may be assigned multiple carriers that may be supported by a single channel card or multiple channel cards at a base station. If multiple FL carriers are handled by different channel cards, there may be channel card communication delays, which may be on the order of a few milliseconds. Although this delay is small, it is typically greater than 1.25ms, which is the time to decode the R-ACKCH, the preferred time to decode the R-CQICH, and the time to schedule a new transmission on the F-PDCH.

If multiple channel cards are used for different FL carriers, the centralized scheduler may incur additional scheduling delay. The additional delay comprises two parts. The first part is the R-CQICH delay to deliver CQI feedback from the channel card processing reverse link decoding to the centralized scheduler. The second part is the delay of the arrival of the selected encoder packet at the channel card processing the F-PDCH transmission. The additional delay may affect the system throughput, but its impact should be limited to a relatively narrow range of speeds and channel models.

For example, if reverse link decoding and forward link transmission are handled by a single channel card, the distributed scheduler may not incur the additional delay described above for the centralized scheduler. This is applicable if no auxiliary carrier is present in the carrier group. However, if a distributed scheduler is implemented on each channel card, it is possible to maintain a separate buffer for each channel card so that data can be co-located with the scheduler. Such a card buffer may be small and a larger buffer may be located at the base station. The distributed scheduler should have enough data to schedule the traffic. The delay to get additional data from the larger buffer may be on the order of a few milliseconds. The card buffer size should take into account the highest possible air data rate to avoid buffer underflow. Although the buffer at the channel card may be relatively small, the reception of RLP frames at the terminal is likely to be out of order. Therefore, it is possible to use a longer detection window for the RLP frame. Conventional early NAK techniques are not practical because they do not take into account that the traffic flow may be out of order in the first transmission. A longer delay detection window in RLP may have a greater impact on TCP. Multiple RLP instances may be used, e.g., one per F-PDCH, but this may result in out-of-order arrival of TCP segments.

The RLP frames are typically pre-compressed at the BSC and appended with MUX overhead. In cdma2000, each RLP frame (including the MUX overhead) contains 384 bits, which are identified by a 12-bit sequence number. The cdma2000RLP header assigns 12 bits to the RLP frame sequence number, which is used to reassemble the RLP frame at the terminal. Given the small size of the RLP frames, this sequence space may not be suitable for high rates, such as the rates available in a multi-carrier configuration. To support high data rates with existing RLPs, RLP frames may be pre-segmented such that the additional 12-bit sequence space used for segmented RLP frames may be reused. Sequence space is not a problem on the reverse link since the RLP frames do not need to be pre-compressed.

The call setup procedure for multi-carrier operation may be implemented as follows. The terminal obtains system information from a forward synchronization channel (F-SYNCH) and overhead messages from a forward paging channel (F-PCH) or a forward broadcast control channel (F-BCCH) transmitted on the primary FL carrier. The terminal may then initiate a call on the primary RL carrier. The base station may assign a traffic channel to the terminal via an Extended Channel Assignment Message (ECAM) sent on the primary FL carrier. The terminal acquires a traffic channel and transitions to a mobile station control traffic channel state, which is one of the mobile station operation states in cdma 2000. In one embodiment, the operating state is defined only for the primary carrier. The base station may then allocate the multiple FL and RL carriers via, for example, a Universal Handoff Direction Message (UHDM). When initializing the traffic channel on the new carrier, the base station may begin sending commands on the forward common power control channel (F-CPCCH) after sending the UHDM. The terminal may start transmitting the R-PICH upon receiving the UHDM. The terminal may send a Handoff Completion Message (HCM), which is a cdma2000 layer three protocol message, to the base station on the primary RL carrier to indicate acquisition of the F-CPCCH.

6.Process and system

Fig. 8 illustrates an embodiment of a process 800 performed by a terminal for multi-carrier operation. The terminal receives an assignment of multiple Forward Link (FL) carriers and at least one Reverse Link (RL) carrier (block 812). The terminal may receive a data transmission on one or more of the multiple FL carriers (block 814). For each FL carrier, the terminal may demodulate and decode the received data transmission separately (block 816). The terminal may also send data on at least one RL carrier (block 818). The terminals may be scheduled for data transmission on the forward and/or reverse links based on various factors, such as availability of system resources, amount of data to be transmitted, channel conditions, and so on.

The terminal may send the designated RL signaling on the primary RL carrier, where the primary RL carrier may be designated from among the at least one RL carrier (block 820). The terminal may receive designated FL signaling on a primary FL carrier, where the primary FL carrier may be designated from a plurality of FL carriers (block 822). For example, a terminal may initiate a call on a primary RL carrier and may receive signaling for call setup on a primary FL carrier. The terminal may select a base station for data transmission on the forward link based on the received signal quality of the primary FL carrier.

The plurality of FL carriers and the at least one RL carrier may be arranged within at least one group. Each group may include at least one FL carrier and one RL carrier as shown in fig. 3. The terminal may receive packets on the FL carriers in each group and may send acknowledgements for the received packets via the RL carriers in the group. The terminal may also send CQI reports for the FL carriers in each group via the RL carriers in that group. One FL carrier in each group may be designated as a group primary FL carrier. The terminal may receive signaling for the RL carriers in each group via the group primary FL carrier.

Fig. 9 illustrates an embodiment of a process 900 for sending an acknowledgement. The terminal receives packets on multiple data channels (e.g., F-PDCH) transmitted via multiple Forward Link (FL) carriers (block 912). The terminal determines an acknowledgement for the packet received on the data channel (block 914). The terminal channelizes the acknowledgement for each data channel with an orthogonal code (e.g., a walsh code) assigned to the data channel to generate a symbol sequence for the data channel (block 916). The terminal repeats the symbol sequence for each data channel a number of times (block 918). The terminal generates modulation symbols for an acknowledgement channel (e.g., R-ACKCH) based on the repeated symbol sequences for the multiple data channels (block 920).

The number of data channels is configurable. For example, due to backward compatibility of cdma2000 revision D, if acknowledgements are sent for only one data channel, then either all zeros or all ones of the orthogonal codes may be used. If the number of data channels is less than a first value (e.g., four), an orthogonal code of a first length (e.g., four chips) may be used. If the number of data channels is equal to or greater than the first value, an orthogonal code of a second length (e.g., eight chips) may be used. The repetition factor may also depend on the number of data channels.

Fig. 10 illustrates an embodiment of a process 1000 for sending Channel Quality Indication (CQI) reports. The terminal obtains full CQI reports for multiple Forward Link (FL) carriers, each full CQI report indicating the received signal quality for one FL carrier (block 1012). The terminal channelizes each full CQI report with an orthogonal code (e.g., walsh code) for the selected base station (block 1014). The terminal sends full CQI reports for multiple FL carriers on the CQI channel at different time intervals (or time slots) (block 1016). The terminal may cycle through multiple FL carriers, select one FL carrier at a time, and send a full CQI report for each selected FL carrier in a time interval designated for sending full CQI reports.

The terminal obtains differential CQI reports for multiple FL carriers for a particular time interval (block 1018). The terminal jointly encodes the differential CQI reports for the multiple FL carriers to obtain one codeword (block 1020). The terminal may select a block code based on the number of FL carriers and may jointly encode the differential CQI report with the selected block code. The terminal may channelize the code words using the orthogonal codes for the selected base station (block 1022). The terminal then transmits the codeword on the CQI channel for a particular time interval (block 1024).

Fig. 11 illustrates an embodiment of a process 1100 for reducing pilot overhead, e.g., in multi-carrier operation. The terminal operates in a control-hold mode that allows transmission of a gated pilot (block 1112). In the control-hold mode, the terminal receives a data channel (e.g., F-PDCH) transmitted on the forward link (block 1114). If no other transmissions are being sent on the reverse link, the terminal sends a gated pilot on the reverse link (block 1116). If there is a transmission being sent on the reverse link, the terminal sends a full pilot on the reverse link (block 1118). For example, the terminal may generate an acknowledgement for a packet received on the data channel, send the acknowledgement with the full pilot on the reverse link, and continue sending the gated pilot on the reverse link after completing transmission of the acknowledgement. The terminal transitions out of the control-hold mode in response to an exit event, which may be signaling to exit the control-hold mode, receipt of a data transmission on the reverse link, etc. (block 1120).

Fig. 8 to 11 illustrate processes performed by the terminal for multi-carrier operation. The base station performs the reverse process to support multi-carrier operation.

Fig. 12 shows a block diagram of an embodiment of a base station 110 and a terminal 120. For the forward link, at base station 110, an encoder 1210 receives traffic data and signaling for the terminal. An encoder 1210 processes (e.g., encodes, interleaves, and symbol maps) traffic data and signaling and generates output data for a plurality of forward link channels (e.g., F-PDCH, F-PDCCH, F-ACKCH, and F-GCH). A modulator 1212 processes (e.g., channelizes, spreads, and scrambles) the output data for the multiple forward link channels and generates output chips. A transmitter (TMTR)1214 conditions (e.g., converts to analog, amplifies, filters, and frequency upconverts) the output chips and generates a forward link signal, which is transmitted via an antenna 1216.

At terminal 120, an antenna 1252 receives the forward link signal from base station 110 and the signals from the other base stations and provides a received signal to a receiver (RCVR) 1254. Receiver 1254 conditions (e.g., filters, amplifies, frequency downconverts, and digitizes) the received signal and provides data samples. A demodulator (Demod)1256 processes (e.g., descrambles, despreads, and channelizes) the data samples and provides symbol estimates. In one embodiment, receiver 1254 and/or demodulator 1256 perform filtering to pass all FL carriers of interest. A decoder 1258 processes (e.g., demaps, deinterleaves, and decodes) the symbol estimates and provides decoded data corresponding to the traffic data and signaling sent by base station 110 to terminal 120. Demodulator 1256 and decoder 1258 may perform demodulation and decoding independently for each FL carrier.

On the reverse link, at terminal 120, an encoder 1270 processes traffic data and signaling (e.g., acknowledgements and CQI reports) and generates output data for a plurality of reverse link channels (e.g., R-PDCH, R-ACKCH, R-CQICH, R-PICH, and R-REQCH). A modulator 1272 further processes the output data and generates output chips. A transmitter 1274 conditions the output chips and generates a reverse link signal, which is transmitted via an antenna 1252. At base station 110, the reverse link signal is received by an antenna 1216, conditioned by a receiver 1230, processed by a demodulator 1232, and further processed by a decoder 1234 to recover the data and signaling transmitted by terminal 120.

Controllers/processors 1220 and 1260 may direct the operation at base station 110 and terminal 120, respectively. Memories 1222 and 1262 store data and program codes for controllers/processors 1220 and 1260, respectively. A scheduler 1224 may assign FL and/or RL carriers to the terminals and may schedule the terminals for data transmission on the forward and reverse links.

The multi-carrier transmission techniques described herein have the following beneficial characteristics:

multicarrier forward link backward compatible with revision D forward link-no changes are made to revision D physical layer

Multi-carrier reverse link backward compatible with revision D reverse link-new backward compatible R-ACKCH and R-CQICH structures that do not affect hardware implementation, and

flexible configurable system-K FL carriers and M RL carriers, where K ≦ NxM and K ≧ M.

The transmission techniques described herein may provide various advantages. First, these techniques allow cdma2000 revision D to support multiple carriers using only, or almost only, software/firmware upgrades. Only certain RL channels (e.g., R-ACKCH and R-CQICH) are changed relatively slightly to support multi-carrier operation. These changes can be implemented with software/firmware upgrades at the base station so that existing hardware, such as channel cards, can be reused. Second, higher peak data rates may be supported on the forward and reverse links. Third, the use of multiple F-PDCHs on multiple FL carriers may improve diversity and thus QoS. The flexible carrier structure enables a gradual increase in data rate with the advancement of VLSI technology.

Headings are included herein for reference, which can help locate particular sections. These headings are not intended to limit the scope of the concepts described therein under, which concepts may be applied to other sections throughout the specification.

Those of skill in the art would understand that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

Those of skill would further appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

The various illustrative logical blocks, modules, and circuits described in connection with the embodiments disclosed herein may be implemented or performed with a general purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

The steps of a method or algorithm described in connection with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may reside within the processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in a user terminal. In the alternative, the processor and the storage medium may reside as discrete components in a user terminal.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features described herein.

Claims (12)

1. An apparatus, comprising:

at least one processor configured to operate in a control-hold mode that allows transmission of a gated pilot, receive a data channel transmitted on a forward link in the control-hold mode, transmit the gated pilot on a reverse link if no other transmissions are being transmitted on the reverse link, and transmit a full pilot on the reverse link if a transmission is being transmitted on the reverse link; and

a memory coupled to the at least one processor.

2. The apparatus of claim 1, wherein the at least one processor is configured to: generating an acknowledgement for a packet received on the data channel, transmitting the acknowledgement with the full pilot on the reverse link, and continuing to transmit the gated pilot after completing transmission of the acknowledgement on the reverse link.

3. The apparatus of claim 1, wherein the at least one processor is configured to: transitioning out of the control-hold mode when signaling to exit the control-hold mode is received or when data is transmitted on the reverse link.

4. The apparatus of claim 1, wherein the data channel is a forward packet data channel (F-PDCH) transmitted on a forward link carrier in a Code Division Multiple Access (CDMA) system.

5. A method, comprising:

operating in a control-hold mode that allows transmission of a gated pilot;

receiving a data channel transmitted on a forward link in the control-hold mode;

transmitting the gated pilot on a reverse link if no other transmission is being transmitted on the reverse link; and

transmitting a full pilot on the reverse link if a transmission is being transmitted on the reverse link.

6. The method of claim 5, further comprising:

generating an acknowledgement for a packet received on the data channel;

transmitting the acknowledgement with the full pilot on the reverse link; and

continuing to transmit the gated pilot after completing transmission of the acknowledgement on the reverse link.

7. The method of claim 5, further comprising:

transitioning out of the control-hold mode when signaling to exit the control-hold mode is received or when data is transmitted on the reverse link.

8. The method of claim 5, wherein the data channel is a forward packet data channel (F-PDCH) transmitted on a forward link carrier in a Code Division Multiple Access (CDMA) system.

9. An apparatus, comprising:

means for operating in a control-hold mode that allows transmission of a gated pilot;

means for receiving a data channel transmitted on a forward link in the control-hold mode;

means for transmitting the gated pilot on a reverse link when no other transmissions are being transmitted on the reverse link; and

means for transmitting full pilots on the reverse link when a transmission is being transmitted on the reverse link.

10. The apparatus of claim 9, further comprising:

means for generating an acknowledgement of a packet received on the data channel;

means for transmitting the acknowledgement with the full pilot on the reverse link; and

means for continuing to transmit the gated pilot after completing transmission of the acknowledgement on the reverse link.

11. The apparatus of claim 9, further comprising:

means for transitioning out of the control-hold mode when signaling to exit the control-hold mode is received or when data is transmitted on the reverse link.

12. The apparatus of claim 9, wherein the data channel is a forward packet data channel (F-PDCH) transmitted on a forward link carrier in a Code Division Multiple Access (CDMA) system.